Chitosan bioactivity has been widely evaluated in seed germination; however, its effects remain inconsistent. Some studies report biostimulant effects, while others manifest inhibitory effects, and some show no effect on germination. A major factor contributing to this poor reproducibility appears to be the variation in the degree of polymerization (X), the molar fraction of acetylation (fA), and the chitosan concentration. However, it remains unclear whether controlling these parameters alone i